1. Field of the Invention
The present invention relates to aircraft communications systems. More particularly, the invention relates to an audio panel for switching audio communications in an aircraft and having enhanced intercom isolation modes for more effectively isolating communications to selected people in the aircraft.
2. Description of the Prior Art
Aircraft frequently receive and transmit communications and navigation signals over a plurality of communication and navigation channels. To simplify the selection and use of different communication and navigation channels, most aircraft include one or more audio panels that include circuitry and controls for switching between the various available communications and navigation channels.
Conventional audio panels include intercom isolation circuitry having several isolation modes that permit audio communications to be selectively delivered to certain people in the aircraft such as the pilot and/or crew and isolated from others such as passengers. Unfortunately, the isolation modes provided by prior art audio panels suffer from several limitations that limit their utility. For example, prior art audio panels typically include an isolation mode that isolates the pilot from everyone else and an isolation mode that isolates the pilot and co-pilot from the passengers, but not an isolation mode that isolates the co-pilot from the pilot and passengers. This is a problem when a co-pilot needs to make a private communication without disturbing the pilot and passengers.
Another problem with the isolation modes of prior art audio panels is that they are typically controlled by multi-position rotary switches. These rotary switches have a finite number of switch positions and therefore cannot be easily configured to provide additional or different isolation modes. Moreover, these rotary-type switches only provide intercom isolation modes for selected communication channels. This is a problem when it is desired to add additional communication channels, such as a wireless phone input, to an audio panel because the rotary switches of known prior art audio panels cannot extend the isolation modes to the new communication channel. Thus, audio communications made over a wireless phone coupled with a prior art audio panel can be heard by all communication stations in an aircraft.
Accordingly, there is a need for an improved audio panel that provides enhanced intercom isolation modes without the limitations set forth above.